Probes for identifying cancer-specific antigens

Abstract

This invention relates to the diagnosis of cancer, and in particular to the identification and detection of cancer-specific antigens, the invention provides antibody probes and methods for using the probes for detection and purification of cancer-specific antigens, and in the preparation of vaccine compositions. Antibodies against cancer-specific antigens are also disclosed and claimed.

1. A method for producing an antibody-secreting cell probe (ASC-probe) against a cancer-specific antigen, comprising the steps of:
 (a) obtaining a biological sample from an animal suffering from a cancer; 
 (b) isolating a population of cells from the biological sample; 
 (c) culturing the cells in vitro in a suitable culture medium, wherein said cells are not subjected to in vitro fusion; and 
 (d) harvesting antibodies produced by lymphoid cells present in the cell population to produce an ASC-probe; 
 in which the cancer is a leukemia. 
 
     
     
       2. A method according to  claim 1 , in which the biological sample is from a tissue area containing lymphoid cells which is close to the site of the cancer. 
     
     
       3. A method according to  claim 1 , in which the biological sample is selected from the group consisting of blood, lymph or lymph node, and bone marrow. 
     
     
       4. A method according to  claim 3 , in which the biological sample is spleen or bone marrow. 
     
     
       5. A method according to  claim 1 , in which the biological sample is a draining lymph node. 
     
     
       6. A method according to  claim 1 , in which the biological sample is not blood. 
     
     
       7. A method according to  claim 1 , in which the cells isolated from the biological sample include B lymphocytes and/or B memory cells. 
     
     
       8. A method according to  claim 1 , in which the sample is subjected to one or more processes for enrichment of lymphocytes or B lymphocytes, or subjected to one or more processes for selectively depleting cell populations which suppress antibody secretion. 
     
     
       9. A method according to  claim 1 , in which the antibodies are separated and purified from the culture medium harvested from the cultured cells. 
     
     
       10. A method of isolating an antigen associated with a cancer, comprising the steps of:
 (a) obtaining a tissue or cell sample from a cancer; 
 (b) culturing the cells in a suitable medium; 
 (c) harvesting antibodies produced by lymphoid cells present in the cell population to produce an ASO-probe; 
 (d) reacting a further sample with the ASC-probe produced in (c) to detect at least one antigen associated with a cancer; and 
 (e) isolating the antigen detected, 
 in which the antigen is associated with a specific stage of development of the cancer. 
 
     
     
       11. A method according to  claim 10 , in which proteins present in the tissue or cell sample are separated by electrophoresis, and the separated proteins are optionally transferred to nitro-cellulose, nylon or other sheets. 
     
     
       12. A method according to  claim 10 , in which in step (d) the product produced by reaction of the further sample with the ASC-probe is detected using a detection assay selected from the group consisting of Western blotting, immunoprecipitation assay, a radioimmunoassay, an enzyme-linked immunoassay, chemiluminescent assay and immunofluorescent assay. 
     
     
       13. A method for purifying a cancer-specific antigen, comprising the steps of:
 (a) isolating a population of cells from the biological sample; 
 (b) culturing the cells in vitro in a suitable culture medium; 
 (c) harvesting antibodies produced by lymphoid cells present in the cell population to produce an ASC-probe; 
 (d) subjecting a crude antigen mixture present in an extract of cancer cells or cancer tissue to affinity chromatography using the ASC-probe prepared in step (c), immobilized on a suitable support; and 
 (e) isolating antigen bound to the immobilized ASC-probe; 
 in which the antigen is associated with a specific stage of development of the cancer.